Traffic signal controller



April 16, 1935. LEROY WOTTRlNG 1,998,038

TRAFFIC SIGNAL CONTROLLER 3 Sheets-Sheet 1 Filed Oct. 26, 1929 1 Q G M i i i 6 w R 7-m 3 gwwxnkoz April 1935. LE ROY WIOTTRING 1,998,038

TRAFFIC SIGNAL CONTROLLER Filed Oct. 26, 1929 I5 Sheets-Sheet 2 v f ZM April 1935. LE ROY WOTTRING 1,998,038

TRAFFIC SIGNAL CONTROLLER Filed Oct. 26, 1929 s Sheets-Sheet 3 amela-.16, 1935 I 1,998,038

UNITED STATES PATENT OFFICE rmmo SIGNAL comonma Le Roy Wottrlng, Lorain, Ohio ApplicationOctober 26, 1929, Serial No. 402.585 4 Claims. (01. 177-331) This invention relates to methods and appafour sets of three lamps each, green, red and ratus for controlling traiiic at street intersections amber in a four way trafilc lamp employing the by means of automatic signals and relates parminimum of make and break contacts. ticularly to methods in which the traflic is con- Another object is to provide a controller of th trolled by signal lamps of different colors enerclass specified provided with improved timing 5 ized in predetermined cyclical sequence. means for timing the periodic illumination of sig- Traflic control systems have been proposed nal lamps in a traflic controlling system. employinglamps of different colors having tramc Other objects will be apparent to those skilled directing significance such for example as green in this art.

for Go, red for Stop and another color such My invention is fully disclosed in the following 10 as amber for Caution. In these systems, in description taken in connection with the accomgeneraL- the amberlamp is illuminated at the panying draw w time of transition from the green to the red and 1 is a d a a View Showing a blame in some cases also from red to green. Systems control system ofthe p amber type and a in which the amber lamp is illuminated on the controller therefor embodying my invention. 15 change from green to red and also on the change Fig. 2 is a chart illustrating the illumination from red to green are sometimes. known as four periods of green, reda d amber lamps in a p way independent amber systems. In other sysamber Sy t 8 0 as Shown in tems which have been designatedas overlapping Fig. 3 is a side elevational view of a motor split amber systems the amber lamp is illumidriven controller of the type diagrammatically 20 nated only concurrently with the green lamp and illustrated in Fig. 1 and by which my invention in the .latter part of the illumination period may be practiced. thereof. 1 Fig. 4 is a view taken from the plane 4 of Fig.

It is one of the objects of my invention to pro- 3 and to a larger scale and with some of the parts vide a system for controlling traflic signal lamps back of the sectional plane being omitted for 25 according to the split amber method which will simplicity. be very simple in principle and mode of operation. Fig. 5 is a view taken approximately from the Another object is to provide a controller or. plane 5 of Fig. 4 and to the same scale as Fig. 3. controlling apparatus for actuating the lamps Fig. 6 is a partial view taken in the direction of of a split amber, tra'fiic control system which will the arrow 6 of Fig. 5 showing an adjustmentfea- 30 be of simple construction, efilcient in operation ture. and in which illumination time. periods may be Fig. 7 is a fragmentary view similar to Fig. 4 adjustably varied. shown in elevation and with some of the parts in Another object is to provide a control apparatus difierent positions.

of the class specified having adjustment features Fig. 8 is a view taken from the plane 8 of Fig. '7. 35 whereby the length of the total cycle of illumina- Fig. 9 is a view taken from the plane 9 of Figs. 4 tion periods may conveniently be changed. to 7.

Another object is to provide acontroller oi the Fig. -10 is a view similar to Fig. 9 but withclass specified in which the relative time periods parts thereof in different positions.

. of the green and red lamp illumination may be Fig. 11 is a partial view similar to Fig. 1 showadl'u tabl'y, varied. ing a modification of my invention, and showing Another object is to provide a controller of the in front elevation a double cam which I may class specified in which the relative length of the employ. time period of the amber lamp illumination may Fig. 12 is a side elevational view of the cam of be adjusted. Fi 11 Another object is to provide a controller of the Fig. 13 is a view similar to Fig. 1 showing anclass specified in which the three aforesaid adother modification.

J'us m nts may be d each dep ndently of Referring to Fig. 1, I have indicated at Inn a the others. four way traflic lamp casing,'which in the simpli- Another object is to provide a controller of the fied form illustrated is generally of box form havclass specified which may be easily adapted to ing sides facing the north, east, south and west Co either a p amber Sy or a four directions of traffic, as indicated by the letters N,

way amber system, as above specified. E, S and W.

Another objectis to provide a controller and On the west and. north sides of the lamp are e system of the split amber type for controlling signal lamps RW, RN etc. The letters R, A and tively, but these in the diagram-have been omitted for simplicity. In the operation of the lamp, the signal lamps are illuminated and extinguished according to apredetermined sequence, as follows: Assuming the traific' to be flowing in the east-west direction,-the green lamp GW will be presented to that 'trafiic and indicate Go, and the red lamp RN will be presented to the north-south traflic and indicate Stop, in accordance with which the traffic will not be moving at the intersection. After a suitable interval of time,

' the amber lamp AW will be illuminated concurrently with the green lamp GW, and this will indicate to the east-west trafiic that the trafic moving directions are about to change. After a predetermined interval of amber and green illumination,.the amber and green lamps AW and GW will be extinguished and the red lamp RW will be illuminated stopping the tramcv in the east-west'direction and at the same time the green lamp GN will be illuminated indicating Go to the north-south trafiic. Similarly, after a suitable interval the amber lampAN wlllburn concurrently with the green lamp GN and indicating a cautionary period to the,north-south trafiic, at the end of which both the amber and green lamps, AN and GN will go out, and the red lamp RN will come on against the north-south traffic and the red lamp RW will go out and the green lamp GW will come on for east-west traflic. This completes the cycle and is the cycle known as the split amber cycle.

This sequence of illumination periods is illustrated in the chart of Fig. 2. The upper bar EW indicates the time periods for the lamps of the east-west direction and the lower bar NS indicates the periods of time for the lamps in the v north-south direction, time being measured as indicated in the horizontal direction.- In the chart, it will be noted that when the green lamp is burning for one direction, the red lamp is burning for the other direction and that in each case, in the latter part of the green period, the amber lamp burns concurrently with the green. In the chart, the successive green and red periods in any one direction are equak-but, as will be understood, they may be made with one longer than the other in accordance with the greater or lesser amount of trafflc in the respective directions.

The above described sequence of signals is effected by the system of connections and controller diagrammatically illustrated in Fig. 1. Stationary switch contacts 3 and 4 have cooperating therewith a movable contact I, shown in the form of an arm pivoted. at 23; the arm has an angularly directed extension 2| von the end of which is a cam follower 22 adapted to roll on a cam 8 which is rotated continuously in the direction of the arrow 25. The roller is kept in contact with the cam by a tension spring 24. Similar stationary switch contacts 5 and 6 have a cooperating movable contact arm 2 pivoted at 23' and having a branch arm 2! and a cam follower 22' also spring pressed against the cam 8 by a spring 24. When the cam 8'rotates, a large diameter portion 26'and a small diameter portion 21 successively cause the contact arms I and 2 to move into engagement with the contacts 3-4 and 5-6 in a sequence to'be described.

In the operation of the system, starting with the controller parts in the position shown, current is supplied by a transformer S and flows by way of wire 9, contact arm I, contact 3, wire H, and thence by wire 28 to a ground connection 29, energizing lamp GW and by wire 30 current flows to ground 3|, energizing lamp RN. Through ground connections the current returns by wire and wire In to the transformer S.

The cam 8 rotates on its shaft 1 and when the cam follower 22' descends to the cam portion 21, current flows by wire ll'energizing lamp AW and through wire l3, contact 6, contact arm 2 and wire Hi the current flows back to the transformer.

On continued rotation'of the cam 8, the cam fol= lower 22 falls and shifts the arm I to contact 4 and this will extinguish lamps' GW and AW and RN and by way of wire l2 will illuminate lamps GN and RW. Subsequently, the cam will raise the follower 22' and move the arm 2 into engagement with contact and current by way of wire l2 will illuminate lamp AN, concurrently with the lamp GN. After a suitable interval of time the cam will raise the follower 22 and move the contact arm from contact 4 to contact 3 and this will extinguish lamps AN and GN and by way of wire II will restore the lamps to their original condition completing the cycle.

By virtue of the above arrangement, traflic travelling toward an intersection facing a red or "Stop signal lamp is charged with the, duty to stop and the drivers will not be tempted to continue in motion into the intersection because of the lighting of any intermediate signal denoting the approach of the green or Go" signal. There is nothing to indicate to them how long it may be displayed and, therefore, there is nothing to tempt them to drive into the intersection before the display of the green Go signal.

On the other hand, the cautionary signal, such as the amber lamp, comes on toward the end of the greenv or Go signal, so that traflic,

facing a green signal and approaching the intersection may either be wamed of the imminence of the red signal, so that they may brake their vehicles and bring them to a stop at the intersection, or, if the amber lamp is not burning, may proceed at full speed through the intersection without hesitation or slowing down and thus aid materially in the free flow and movement .of traflic.

It will be observed from 'Fig. 1 that the split amber? cycle of lamp illumination, above described, may be accomplished according to my invention with four make and break contacts only, such as 3, 4, 5 and 6 and with only four control wires to the lamps, namely wires H, I 2, I3 and Hi. It will also be observed that a single cam 8 and two cam followers 22 and 22' are all that are needed to actuate the contacts.

In Figs. 3 to 10 inclusive, is illustrated a preferred form of controller mechanism having the circuit make and break functions of the diagrammatic controller of Fig. 1. In Fig. 3, the stationary contacts 3, 4, 5 and 6 are reproduced as of the butt contact type. The contacts 3 and 4 are mounted in posts 40 and 4 I rising from the outside surface of a controller housing 42. The contacts are insulated from the posts by insulating washers 43 and bushings, not shown, of well known construction, and the contacts 3 and 4 are provided with terminal nuts 45 between which are secured conductor terminals 45 to which are connected the conducting wires and I2, respectively. Rotatably mounted on a pivot post 41 on the controller housing 42 is a a generally vertically arranged switch arm 2| carrying on its upper end a generally horizontal resilient extension 48 on the extremity of which is mounted a double butt contact adapted to reciprocate into engagement with the stationary contacts 3 and 4 and. by means of the flexible extension 48 to have spring pressed wiping contact therewith, when the arm 2| is oscillated in a manner to be described.

The switch arm 2| is resiliently held in a clockwise direction by a flat spring 49 secured to the arm as at 50 and riding upon an insulated post 5| on the casing.

Rotatably mounted upon a pivot post 5| rising from a contact support 52, to be more fully described, is a switch arm 2| normally held in a clockwise direction by a wire spring 53 one end of which engages the arm 2| at 54', the spring being wound about the post 5| and its other end riding upon an insulated post 54 on the contact support 52. The arm 2| has a vertical resilient extension 55 having on its extreme end a butt contact 22 similar to the contact adapted to engage the contacts 5-8 with a spring pressed wiping contact. The contacts 5 and 5 .may be constructed similarly to the contacts 3 and 4 and insulated from supporting branches 56-56 on the contact support 52 by insulating parts 51 in a well known manner; and the contacts 5 and 8 may have terminals 58-58 connected thereto and communicating with conducting wires l4 and I3, re-

spectively.

A conducting wire 9 is connected to the extension 48 and contact by a terminal connection as at 59 and a wire I0 is connected with arm 55 and contact 22 by a terminal connection 88. Upon the lower ends of the arms2| and 2|, respectively, are mounted fibre blocks or cam followers 22 and 22, respectively, adapted to ride upon the surface of a cam, to be described, and thereby adapted to be moved counter-clockwise and clockwise about their pivots 41 and 5| and it will now be understood that when the arms 2| and 2| are so moved, the contacts and contacts 2-2 will be moved to make and break connection with the stationary contacts 3, 4, 5 and 5 respectively, to establish connections through the wires 9, II and I2 and wires I0, l3 and H, as has been described in connection with Fig. 1.

The said cam and the mechanism for rotating it will now be described. Referring to Figs. 3 and 4, the controller housing 42 consists generally of a front portion 65 and a rear portion 66 which may be secured together with a sealed joint, as at 61 in a known or suitable manner. Into the front portion 65 is screwed a shaft bearing 88 having a flange 69. The inner end 18 of the bearing 68 may, if des red, be slightly peened over to retain it against accidentally unscrewing. Between the flange 69 and the face 1| on the wall of the housing portion is clamped a bearing head 12 formed on the contact support 52 which has above been described. The head 12 is bored out as at 13 to fit a smooth bearing portion of the bearing .88 and the bearing support 52 may thus be adjustably rotated about the axis of the bearing 68. To hold the head and bearing support in any adjusted position, a friction washer 14 is interposed between the head 12 and the face above referred to and the washer 14 is preferably made of resilient material and dished out of planular form and riveted in one or more places as by rivets 15 to the head I2. Thus, when the bearing 68 is screwed in, the washer I4 exerts axially a resilient thrust causing friction on the 'fiange 89 and on the face I I. The washer 14 may,

if desired, be provided on its periphery with gear teeth and by means of gears, not shown, the washer thus may serve also to rotate the head 12 to which it is riveted and thus adjustably rotate the contact support 52. When adjusted, the contact support 52 will take up different clockwise or counter-clockwise positions, as viewed in Fig. 3 to change the angular displacement or relative circumferential interval between' the cam follower blocks 22 and 22', for a purpose to be described.

Within the bearing 58 is rotatably mounted a cam shaft 16 projecting into the housing 42 and having secured thereto a toothed gear TI I by which the shaft may be rotated. By a train of meshed reduction gears including the gear 11 and spur gears 18, 19, and 88, a worm gear 8|, and finally a worm 82 meshed with the worm gear, the shaft I5 may be slowly rotated, power being supplied to the worm 82 by a motor and connected elements shown particularly in Fig. 5 and to be described. The cam 8 mounted to rotate with the shaft 18 comprises two leaves 83 and 84, arranged in a plane transversely to the shaft 18. The leaf 83 is pinned to the shaft 16 as at 85 and is rotatably driven thereby. The leaf 84 is provided with a hub 86 rotatably mounted on the shaft 16 to adjust its angular position thereon, but in any adjusted position is driven by the shaft 16 by a key 81 in the hub, a longitudinal key way 88 in an adjusting indexed head 89, and a pin 90 secured in the head and entering one of several recesses 9| in a flange 92 pinned as at 93 to the shaft 16. The head 89 has an internal hub 94 rotatably and longitudinally slidably mounted on the hub 86 of the cam leaf 84 and is retained in its outward axial position in engagement with the flange 92 along an inner face 95 of the flange and with the pin 99 of the head in a hole 9|c in the flange by a spring 96 abutting between the head and the cam leaf 84. The leaf 84 may thus be angularly adjusted around the axis ofthe shaft 16 relative to the'leaf 83 by manually sliding the head 89 inwardly on the hub 86, to free the pin 90-from the flange 92 and then by rotating the head 89 and cam hub 85 on the shaft 16 to bring the pin 99 into registration with another hole in the head 92 and releasing the head 89, whereupon the spring 96 will cause the pin 90 to enter the said hole and lock the head 89 and the cam leaf 84 in the new adjusted position relative to the shaft 16 and therefore relativeto the cam leaf 83. The flange 92 thus referred to is shown separately in Fig. 8 where five adjustment holes 9|a to 9 hi are shown.

In Fig. '7, the head is shown in its inner spring pressed position at which it may so be turned, the pin 98 being shown withdrawn from its hole in the flange 92. The cam leaves 84 and 83 are preferably of the same profile; shown in Fig. 9, and in that figure the cam leaf 83 is directly behind the cam leaf 84. In Fig. 10, the cam leaf 84 is shown adjusted counter-clockwise relative to the cam leaf B3 and this figure illustrates one creased and the portion 21 may be adjustably decreased when the cam leaf 84 is adjustably rotated and as illustrated in'Fig. 10. The two leaves of the cam cooperateas a single cam 0, when the shaft 16 is rotated for the purpose described in connection with Fig. -1, the cam followers 22 and 22', shown in Fig. 3 being made axially long enough to cover both cam leaves 83 and 84, as indicated in broken lines at 22 in Fig. 4. The cam 8, is shown in dotted lines in Fig. 3 with the cam followers 22 and 22' in engagement therewith.

For rotating the cam shaft I6 through the chain of gears above described, the mechanism illustrated in Fig. 5 is preferably employed. The

electric motor I05 which may be of any suitable or known type, and suitably mounted on the housing 42, as at I06, has a motor shaft I 01 extending into the housing 42 on which is formed or mounted or to which is connected or secured the worm 82 above mentioned. The shaft I01 may have a bearing support at or adjacent its driven end in the frame of the motor or in the controller housing as at I08 and to support the outer end of the shaft, an adjustable end thrust bearing II screw threaded into the Wall of the housing, as at III, is provided, having an axial recess II2 into which a trunnion I09 of the motor shaft is inserted and in which it has rotative and end thrust bearing.

This construction permits additionally of the use of a simple speed controlling mechanism whereby the speed of the motor shaft, and therefore of the cam shaft above referred to, may be adjusted and maintained at adjusted speeds, and

this mechanism will now be described. Secured to the motor shaft as by a set screw I I 3 is a collar H4 to which one end each of a plurality of fiat thin metal resilient governor springs II5 are.se-' cured as by screws H6. The other end of the springs are secured as by springs II I to a similar collar II8 secured to a longitudinally slidable sleeve I I9 on the shaft. Governor weights I20 are secured to the springs I I5. Mounted to rotate with and move with the collar H8 is a friction wheel I2I adapted to have suitable friction contact with a shoe I22, preferably of felt, leather or the like supported by the roof of the housing 42 by a stud I23 threaded in the housing and having clamp nuts I24-I24 on each side of the shoe I22. The stud I23 passes outwardly through the housing, as shown at I25 in Fig. 4. By this construction, the radial position of the shoe I22 on the friction wheel I2I may be adjustably varied and fixed.

Upon rotation of the motor shaft, the springs II5, weights I20 and friction wheel I2I rotate with it; the centrifugal movement of the weights I20 will draw the friction wheel I2I into contact with the shoe I 22, the sleeve II 9 sliding on the motor shaft for this purpose, and the shoe I22 and wheel I 2| will function as a brake load on the motor, limiting speed to a definite amount.

To adjustably vary the speed, the normal position of the wheel I2I may be shifted by longitudinally shifting the shaft I01 and this in turn is effected by adjustably screwing thebearing IIO inwardly or outwardly of the-housing 42. In this connection, the motor shaft may be given thrust away from the motor by means of the reaction between the worm 82 and the worm wheel 8| and also by means of armature reactions to keep out lost motion in the end thrust bearing I09--I I0,

and to thus contribute to accurate sensitive speed regulation.

It will now be understood that by means of the motor I05. power is transmitted to rotate rection, say east and'west traffic) a Go interval, concurrently at its end with a cautionary interval, and a CStQp interval, the Go interval occurring when the cam follower 22 is on the cam portion 26, the Stop" interval when the cam follower 22 is on the cam portion 21 and the cautionary'interval when the cam follower 22 is on the portion 21 and the cam follower 2| is on the portion 26. By referring .to Fig. 1, it will be clear that to vary the cautionary period, the cam followers 22 and 22' may be moved closer together or farther apart and in my improved controller, this is very easily and conveniently effected by manually rocking the contact support 52 clockwise or counter-clockwise, as desired, which movement moves the cam follower 22'. a

It will also be apparent from Fig. 1 that the relative lengths of the Go and Stop periods will be in proportion to the relative lengths of the cam portions 26 and 21 and this relative length may be adjustably varied in my improved controller and the-adjustment fixed as above described.

I find that a suitable range for this adjustment will be given with two cam leaves having cam portions 26 equal to approximately a fourth of the revolution of the cam and providing adjusted positions in which they may be registered with each other, as in Fig. 9 or relatively moved to an extreme position, as in Fig. 10, wherein the cam portion 26 of one leaf begins where that of the other leaves off.

By means of a reference calibration mark I30, Fig. 7, and suitable calibration indicia, A, B, C, D and E on the head 89, corresponding to the several holes 9I,in the flange 92, the controller may be calibrated for definite Stop and Go periods. The total numberof seconds required for a complete cycle, or complete rotation of the cam, may be adjusted by screwing inwardly or outwardly the bearing H0, Fig. 5, and by means of a hand I 3|, Fig. 5, secured to 'the bearing IIO to rotate therewith and by means of a calibrated dial I32 secured to the housing against rotation as by a screw I34, the speed of the motor, and, therefore, the length of a cycle may. be indicated. The dial I32 is preferably calibrated in seconds by calibration marks I33.

'I'hus, the length of the entire cycle can be adjusted at any time simply by turning the hand I3I to the suitable calibration mark on the dial I32; Division of this cycle into Go and Stop intervals may be determined simply by rotatably adjusting the head 09 in accordance with its calibration marks. Finally, the relative length of the cautionary interval may be adjusted by simply rocking the 'contact support 52.

While I have described my improved controllermechanism in connection with the preferred or overlapping split amber method of traific control, my controller has a further advantage in being simply and easily adapted to control trafiic systems operating on the four Way independent amber method. To adapt my controller to this use, it is only necessary to prosystem.

vide it with cam leaves 83 and 84 of suitable profile and to provide cam followers cooperating independently with each other, each with a respective leaf of the cam.

This adaptation of my invention is illustrated in Figs. 11 and 12. In Fig. 11 the movable switch contact 200 cooperates with the stationary contacts 20| and 202 to respectively energize the Go and Stop signals and themovable contact 203 cooperates with the stationary contact 204 to energize the amber signals. The cam leaf 205 actuates the movable contact 200 through the cam follower 206 and the cam leaf 201 similarly actuates the movable contact 203,

through the cam follower 208. It is not deemed necessary in view of. the complete foregoing description of the split amber operation to describe or. show the circuit connections in full in connection with Fig. 11. It is believed suflicient to say that in connection with the cam leaf 205, when the cam follower 20.6 is on the cam portion 209, the contact at 20! will be closed; when the cam follower is on the cam portion M0 the contact 200 will be in an intermediate oropen contact position; when the cam follower is on the cam portion 2, the contact 202 will be closed. In connection with the cam leaf 201, when the cam follower 208 is on the cam portion 2|2, the contact at 204 will be open and when the cam follower 208 is on the cam portion 2l3, said contact will be closed.

The cam leaves 201 and 205 are positioned on their shaft 2| 4 so that the cam follower 206 comes on, the cam portion 2l0- at the same time the cam follower 208 comes on the cam portion 2I3. Thus, it will be seen that the contact 204 will be closed to energize the amber lamps each time that the contact 202 is in the intermediate position between the Go and Stop positions, 1. e., when both the Stop and Go lamps are extinguished.

In Fig. 12 the two cam leaves 20! and 205 are illustrated and their respective cam followers 206 and 208 are indicated.

Another adaptation of my controller and con- I trol system by which the four-way independent amber method of, control may be effected there- 'with is illustrated in Fig. 13. In this modification, the controller is unchanged from its form as employed for the overlapping-split amber" method and as described-hereinbefore, it being necessary with this modification only to change some of the electric circuit connections of the Referring to Fig. 13, the wire I I from the contact 3 may energize a lamp GW and a lamp RN and the wire I2 connected to the contact 4 may energize a. lamp GN or a lamp RW. A wire 250 connected directly to the switch arm 2 may energize lamps AW and AN. The contact 5 is connected to the contact 4 by wire 25I and the contact 6 is connected to the contact 3 by a wire 252. Energy is supplied from the transformer secondary S by the wire 9.

In the operation of the four-way independent amber method according to the system of connections in Fig, 13, when the cam 8 is in the position shown, current may fiow from wire 9 to wire H to energize the GW and RN lamps. When the cam is rotated until the switch arm 2 operates to engage contact 6, current flows ad-' ditionally through wire 252, contact 6 and wire 250 to energize lamps AW and AN concurrently with the energization-of the lamps just described. Further movement of the cam 8 will move the arm I to engage the contact 4 and thereupon all the energized lamps will be deenergized and current will flow from wire S through wire I2 and energize the lamps RW and GN only.

Upon continued rotation of the cam 8, the switch arm 2 will again be actuated in the other direction to engage contact 5 and then current will flow from contact 4 by wires 25l and 250 to energize lamps AW and AN concurrently with the other lamps.

Upon a further movement of the cam 8, the arm I will be returned to the contact 3 deenergizing the lamps just described and energize those which were energized in the first instance, thus completing the cycle.

My invention is not limited to the exact details of construction shown and described, since my invention may be embodied in other and various structures without departing from the spirit of my invention or sacrificing its advantages.

I claim:-

1. In an electric system for trafiic control, a stop, caution and go signal for the 'trafiic in a first direction, a stop, caution andgo signal for the trafiic in a second direction, a source of current supply and circuits and contacts for energizing the signals comprising a first'contact and a first and second contact associated therewith, a second contact and a first and second contact associated therewith, circuit connections for energizing the go signal in the first direction and the stop signal in the second direction including the first contact and its first associated contact; circuit connections for energizing the go signal in the second direction and the stop signal in the first direction including the first contact and the second of its associated contacts; circuit connections for energizing the caution signal in the first direction including the first contact, the first of its associated contacts, the second contact and the first of its pair of associated contacts; and circuit connections for energizing the caution signal in the second direction including the first contact, the second of its associated contacts, the second of the associated contacts of the second contact, and the said second contact, and means-- effecting cyclic operation of the contacts whereby the go signal in the first direction and the stop signal in the second direction will be concurrently energized for a predetermined time inter: val, and the cautionary signal in the first direction will be subsequently concurrently energized for a shorter predetermined time interval, then concurrently all of the aforesaid energized signals will be de-energized and the go signal in the second direction and the stop signal in the first direction will be energized for a predetermined time interval, and subsequently concurrently the caution signal in the second direction will be energized for a predetermined time interval, and then concurrently all of the said energized signals will be de-energized, and the cycle thus determined will be continuously repeated, and means for varying the relative time intervals allotted to each of the signals.

2. In an electric system'for traffic control, a stop, caution, and go signal for the trafilc in a first direction, a. stop, caution, and go signal for the trafilc in a second direction, a source of current supply and circuits and contacts for-energizing the signals comprising a first contact and a first and second contact. associated therewith, a second contact and a first and second contact associated therewith, circuit connections for energizing the go signal in the first direction and the stop signal inthe seconddirection including the first contact and its first associated contact; cir- 'cuit connections for energizing the go signal in the second direction and the stop signal in the first direction including the first contact and the second of its associated contacts; circuit connections for energizing the caution signal in the first direction including the first contact, the first of itsassociated contacts, the second contact and the first of its pair of associated contacts; and circuit connections for energizing the caution signal in the second direction including the first contact, the second of its associated contacts, the second of the associated contacts of the second contact, and the said second contact, and means efiecting cyclic operation of the contacts whereby the go signal in the first direction and the stop signal in the second direction will be concurrently energized for a predetermined time interval only, and the cautionary signal in the first direction will be energized for a predetermined time interval only beginning after the initial energization of the said go and stop signals, and then after the termination of the go and stop signal time interval and substantially at the termination of the cautionary signal time interval, the go signal in the second direction and stop signal in the first direction will be energized for a predetermined time interval only, and the cautionary signal in the second direction will be energized for a predetermined time interval only beginning after initial energization of the last-mentioned go and stop signals, and then after the termination of the last-named go and stop signal time interval and substantially at the termination of the last-named cautionary signal time interval, the above-described cycle will be repeated.

3. An electric system as described in claim 2 and in which means is provided for varying the relative time intervals allotted to each of the signals.

4. In an electric system for trafiio control, a

stop, caution and go signal for the traflic in a first direction, a stop, caution and go signal for the traflic in a second direction, a source'of current supply and circuits and contacts for energizing the signals comprising a first contact and a first and second contact associated therewith.-

a second contact and a first and second contact tacts; circuit connections for energizing the cau-' tion signal in the first direction including the first contact, the first of its associated contacts, the second contact and the first of its pair of associated contacts; and circuit connections for energizing the caution signal in the second direction including the first contact, the second of its associated contacts, the second of the associated contacts of the second contact, and the said second contact, and means effecting cyclic operation of the contacts whereby the go signal in the first direction and the stop signal in the second direction will be concurrently energized for a predetermined time interval, and the cautionary signal in the first direction will be subsequently concurrently energized for a predetermined time interval, then concurrently all of the aforesaid energized signals will be ole-energized and the go signal inthe second direction and the stop signal in the first direction will he energized for a predetermined time interval, and subsequently concurrently the caution signal in the second direction will be energized for a predet'ermined time interval, and then concurrently all of the said energized signals will be de-energized and the cycle thus determined will be continuous- 

